JP2023540557A - energy storage cell - Google Patents

Abstract

an energy storage cell (100 )It has been known. Each electrode has a corresponding current collector (115, 125), with the longitudinal edge of the negative electrode projecting from one of the end faces (104b, 104c) and the longitudinal edge of the positive electrode protruding from one of the end faces (104b, 104c). The electrodes are designed and/or arranged relative to each other within the composite such that they protrude from one another. The composite body (104) is oriented axially within the housing, the housing comprising a tubular metal housing part (101) having a terminal circular opening (101c), and the winding casing (104a) comprising a tubular housing part (101c). 101) so as to be placed in contact with the inner surface (101b). In order to electrically contact one of the electrodes, the cell (100) directly contacts one of the longitudinal edges (115a, 125a) projecting from one end face, and a contact element (110) connected by welding to the part. According to the invention, the terminal circular opening (101c) of the tubular housing part (101) is to be closed in an air-tight and liquid-tight manner by the contact element (110). For this purpose, the contact element (110) has a circular edge (110a), the contact element (110) curves when the pressure in the housing exceeds a threshold, and the contact element (110) has a first longitudinal edge. is or includes a metal membrane (111; 151) between which electrical contact is removed.

Description

The invention described below relates to an energy storage cell comprising an electrode-separator assembly.

Electrochemical cells are capable of converting stored chemical energy into electrical energy through redox reactions. Electrochemical cells generally include a positive electrode and a negative electrode separated from each other by a separator. During discharge, electrons are released at the negative electrode as a result of an oxidation process. The result is an electron current that can be drawn in by an external consumer. Electrochemical cells serve as an energy source for consumers. At the same time, an ionic current corresponding to the electrode reaction is generated within the cell. This ionic current passes through the separator and is enabled by the ionically conductive electrolyte.

A cell is called a secondary battery if the discharge is reversible, that is, if the conversion of chemical energy to electrical energy that occurred during the discharge can be reversed and thus recharge the cell. It is customary in secondary batteries to designate the negative electrode as an anode and the positive electrode as a cathode, which relates to the discharge function of an electrochemical cell.

Secondary lithium-ion batteries are used in many applications today because they are capable of supplying high currents and are notable for their relatively high energy density. Secondary lithium-ion batteries are based on the use of lithium, which can be shuttled between the cell's electrodes in the form of ions. The negative and positive electrodes of lithium ion batteries are usually formed from electrodes known as so-called composite electrodes, which, in addition to electrochemically active components, also contain electrochemically inert components.

Useful electrochemically active components (active materials) for secondary lithium-ion batteries are, in principle, all materials capable of absorbing lithium ions and releasing them again. Here, carbon-based particles, such as graphitic carbon, are often used for the negative electrode. Other non-graphitic carbon materials suitable for lithium intercalation can also be used. In addition, it is also possible to use metallic and semimetallic materials that can be alloyed with lithium. For example, the elements tin, aluminum, antimony, and silicon can form intermetallic phases with lithium. Examples of active materials that can be used for the positive electrode are:

It includes lithium cobalt material (LiCoO ₂ ), lithium manganese oxide (LiMn ₂ O ₄ ), lithium iron phosphate (LiFePO ₄ ), or derivatives thereof. The electrochemically active material is usually present in particulate form in the electrode.

As electrochemically inert component, the composite electrode generally comprises a two-dimensional and/or ribbon-like current collector, for example a metal foil, which serves as a carrier for the active material. The current collector for the negative electrode (anode current collector) can be formed from copper or nickel, for example, and the current collector for the positive electrode (cathode current collector) can be formed from aluminum, for example. In addition, the electrode contains as electrochemically inert ingredients an electrode binder (e.g., polyvinylidene fluoride (PVDF), or another polymer, e.g., carboxymethyl cellulose), a conductivity-improving additive, and other additives. But that's fine. The electrode binder ensures the mechanical stability of the electrode and also, in many cases, the adhesion of the active material to the current collector.

Lithium ion batteries typically include a lithium salt solution, such as lithium hexafluorophosphate (LiPF ₆ ) in an organic solvent (eg, carbonic ethers and esters) as the electrolyte.

In the manufacture of lithium ion batteries, composite electrodes are combined with one or more separators to provide a composite body. In this case, the electrode and separator are usually joined together under pressure and optionally by lamination or adhesive bonding. The basic ability of the cell to function can be established by impregnating the assembly with an electrolyte.

In many embodiments, the composite body is formed as or processed to provide a winding. Generally, the composite body includes an electrode/separator/negative electrode sequence. Often, the composite body is made as a so-called bicelle, the expected sequence of which is negative electrode/separator/positive electrode/separator/negative electrode, or positive electrode/separator/negative electrode/separator/positive electrode. .

The automotive sector, electric bicycles, or even other applications requiring high energy, such as tools, require lithium-ion batteries with maximum energy density, capable of simultaneously injecting high currents during charging and discharging. .

In many cases, cells for the aforementioned applications take the form of round cylindrical cells, for example with a shape factor of 21×70 (diameter×height in mm). Cells of this type always contain a composite body in the form of a winding. Modern lithium-ion batteries of this form factor can already achieve energy densities of up to 270 Wh/kg. However, this energy density is believed to be only an intermediate step. The market is already demanding cells with even higher energy densities.

However, in the development of improved electrochemical cells, energy density is not the only factor to keep in mind. Critical parameters are the internal resistance of the cell, which must be kept to a minimum to reduce power losses during charging and discharging, and the thermal connection of the electrodes, which can be important for temperature regulation of the cell. These parameters are also very important for circular cylindrical cells containing composite bodies in the form of windings. During fast charging of cells, power loss can lead to heat accumulation in the cells, which can lead to large thermomechanical stresses and subsequent deformation and damage of the cell structure. The risk is amplified if the electrical attachment of the current collector is done via a separate electrical output conductor lug that projects axially from the rolled composite body. This is because during charging or discharging, localized heating can occur in these output conductor lugs under high loads.

WO 2017/215900A1 describes an electrode-separator assembly and a cell in which the electrodes are ribbon-like and in the form of windings. Each electrode has a current collector provided with electrode material. Electrodes of opposite polarity are arranged offset from each other in the electrode-separator assembly such that the longitudinal edge of the current collector of the positive electrode protrudes from the winding on one side and the current collector of the negative electrode protrudes from the winding on one side. It protrudes from the winding on the other side of the longitudinal edge of. For electrical contacting of the current collector, the cell has at least one contact element which rests against one of the longitudinal edges so that a linear contact zone is provided. The contact element is joined to the longitudinal edge along a linear contact zone by welding. This allows electrical contact to be made over its entire length to the current collector and thus also to the corresponding electrode. This significantly reduces the internal resistance within the described cell. As a result, the generation of high currents can be managed very well.

Nevertheless, failures can occur as a result of aging of electrochemical cells, mechanical damage, incorrect charging, and several other reasons, and these result in unnecessary heating or Gas evolution may occur, resulting in an uncontrolled increase in pressure within the cell. In such cases, electrochemical cells generally have safeguards. In this connection, special emphasis should be placed on the use of so-called CIDs (Current Interrupting Devices), which break the electrical contact between the terminal and the electrodes connected to it in the event of excessive gas pressure in the cell. be.

However, CIDs are relatively complex structures and are typically installed as additional assemblies. CIDs occupy a relatively large amount of space within the cell housing, which works against the goal of improving energy density.

The object of the invention is to be characterized by an improved energy density and a uniform current distribution over the maximum area and length of its electrodes compared to the prior art, and at the same time to be superior with respect to its internal resistance and its active cooling properties. An object of the present invention is to provide an energy storage cell having the following characteristics. However, the cells must also feature, inter alia, improved safety and manufacturability.
This object is achieved by an energy storage cell with the features of claim 1. Preferred constructions of the cells will become apparent from the dependent claims.

The energy storage cell of the invention always has at least the following features: a. ~j. has:
a. The cell comprises an electrode-separator assembly having an anode/separator/cathode sequence.
b. The electrode-separator assembly takes the form of a cylindrical winding having two terminal end faces and a wrapped jacket.
c. The cell comprises a housing comprising a metallic tubular housing part having a terminal circular opening.
d. An electrode-separator assembly in the form of a wire wound wire is axially aligned within the housing such that the wound jacket abuts the interior of the tubular housing part.
e. The anode is ribbon-shaped and includes a ribbon-shaped anode current collector having a first longitudinal edge and a second longitudinal edge.
f. The anode current collector comprises a strip-shaped main region provided with a layer of negative electrode material and a free edge strip extending along a first longitudinal edge and free of electrode material.
g. The cathode includes a ribbon-shaped cathode current collector that is ribbon-shaped and has a first longitudinal edge and a second longitudinal edge.
h. The cathode current collector comprises a strip-shaped main region provided with a layer of positive electrode material and a free edge strip extending along a first longitudinal edge and free of electrode material.
i. The anode and cathode are arranged such that the first longitudinal edge of the anode current collector extends over one of the terminal end faces and the first longitudinal edge of the cathode current collector passes over the other of the terminal end faces. , formed and/or arranged with respect to each other within an electrode-separator assembly.
j. The cell comprises an at least partially metallic contact element in direct contact with one of the first longitudinal edges and connected to this longitudinal edge by welding.

Preferred embodiments of the electrochemical system In principle, the invention includes energy storage cells, regardless of their electrochemical configuration. However, in particularly preferred embodiments, the energy storage cell of the invention is a lithium ion battery, especially a secondary lithium ion battery. It is therefore possible in principle to use for the anode and cathode of the energy storage cell all electrode materials known for secondary lithium-ion batteries.

The active material used in the negative electrode of the energy storage cell of the invention in the form of a lithium-ion battery is carbon-based particles, preferably also in particulate form, capable of intercalating lithium, such as graphitic carbon materials. Alternatively, it may be a non-graphitic carbon material. Alternatively or additionally, lithium titanate (Li ₄ Ti ₅ O ₁₂ ) or a derivative thereof can be included in the negative electrode, preferably also in particulate form. In addition, the negative electrode as active material comprises at least one material from the group of silicon, aluminum, tin, antimony, or compounds or alloys of these materials, capable of reversibly intercalating and deintercalating lithium; For example, silicon oxide can be included, optionally in combination with carbon-based active materials. Tin, aluminum, antimony, and silicon can form intermetallic phases with lithium. Here, especially in the case of silicon, the ability to absorb lithium exceeds the value of graphite or comparable materials, several times as much. It is also possible to use thin anodes of metallic lithium.

Examples of useful active materials for the positive electrode of the energy storage cells of the present invention in the form of lithium ion batteries include lithium metal oxide compounds and lithium metal phosphate compounds, such as LiCoO ₂ and LiFePO ₄ . Also very suitable are lithium nickel manganese cobalt oxide (NMC) with the molecular formula _{LiNix Mny} Co _z O ₂ (x+y+z is typically 1), lithium manganese spinel with the molecular formula LiMn ₂ O ₄ (LMO), or lithium nickel cobalt aluminum oxide (NCA) with the molecular formula LiNix Co _y Al _{z O 2} (x+y+z is typically 1). Their derivatives, for example lithium nickel manganese cobalt aluminum with the empirical formula Li _1.11 (Ni _0.40 Mn _0.39 Co _0.16 Al _0.05 ) _0.89 O ₂ , or Li _1+x MO compounds Oxides (NMCA) and/or mixtures of these materials can also be used. The cathode active material is also preferably used in particulate form.

In addition, the electrodes of the energy storage cells of the present invention in the form of lithium ion batteries preferably include electrode binders and/or additives to improve electrical conductivity. The active material is preferably embedded in a matrix of electrode binder, and adjacent particles in the matrix are preferably in direct contact with each other. The conductive agent plays a role in increasing the electrical conductivity of the electrode. Typical electrode binders are based on, for example, polyvinylidene fluoride (PVDF), polyacrylate, or carboxymethyl cellulose. Typical conductive agents are carbon black and metal powders.

The energy storage cell of the invention preferably comprises, in the case of lithium ion batteries, an electrolyte based on at least one lithium salt, for example in an organic solvent (for example an organic carbonate, or a cyclic ether, for example THF or Lithium hexafluorophosphate (LiPF ₆ ) dissolved in a mixture of nitrile, nitrile, and nitrile. Other usable lithium salts are, for example, lithium tetrafluoroborate ( _LiBF4 ), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), and lithium bis(oxalate)borate. (LiBOB).

Preferred Embodiments of Separators The electrode-separator assembly comprises at least one separator, preferably in the form of a ribbon, more preferably two separators in the form of a ribbon, the or each separator having a first and a second longitudinal edge. has a department.

The separator is preferably formed from an electrically insulating polymer film. Preferably, the separator is permeable to the electrolyte. For this purpose, for example, the polymer membrane used may have micropores. The film may also be composed of polyolefins or polyetherketones, for example. As separators it is also possible to use non-woven and woven fabrics made of polymeric materials or other electrically insulating sheet-like structures. Preferably, a separator with a thickness in the range 5 μm to 50 μm is used.
In some embodiments, the separator of the composite may also be one or more layers of solid electrolyte.

Preferred Construction of a Wire-Wound Electrode-Separator Assembly In a wire-wound electrode-separator assembly, the ribbon anode, ribbon cathode, and ribbon separator are preferably in the form of a spiral winding. Take. To produce an electrode-separator assembly, a ribbon-like electrode is fed to a winding device along with a ribbon-like separator and preferably spirally wound around a winding axis therein. In some embodiments, the electrodes and separators are wound for this purpose onto a cylindrical or hollow cylindrical winding core that is placed on a winding mandrel and remains within the winding after the winding operation. The wrapped jacket may be formed, for example, by a polymer membrane or an adhesive tape. It is also possible that the wound jacket is formed by one or more separate windings.

Preferably, the longitudinal edges of the separator form the end faces of the electrode-separator assembly in the form of a winding. The longitudinal edge of the anode current collector and/or cathode current collector protruding from the terminal end face of the winding is preferably 5000 μm or less, preferably from the end face formed by the longitudinal edge of the separator. It is more preferable that the protrusion is 3500 μm or less.

More preferably, the longitudinal edge of the anode current collector protrudes from the end face of the winding by 2500 μm or less, more preferably by 1500 μm or less. More preferably, the longitudinal edge of the cathode current collector protrudes from the end face of the winding by 3500 μm or less, more preferably by 2500 μm or less.

Preferably, the ribbon-shaped anode and the ribbon-shaped cathode are such that the first longitudinal edge of the anode current collector extends beyond one of the terminal end faces, and the first longitudinal edge of the cathode current collector extends beyond the terminal end face. They are offset from each other within the electrode-separator assembly to ensure that they overlap the other of the end faces.

Preferred Embodiments of the Current Collector The current collector of the energy storage cell serves to make electrical contact over the largest area to the electrochemically active components present in the corresponding electrode material. The current collector is preferably made of metal, or has at least a surface layer metallized. In the energy storage cell of the invention in the form of a lithium-ion battery, suitable metals for the anode current collector are, for example, copper or nickel, or other electrically conductive materials, especially copper alloys and nickel alloys, or nickel-coated metals. be. Stainless steel is also generally useful. Suitable metals for the cathode current collector in the case of the energy storage cells of the invention in the form of lithium ion batteries are, inter alia, aluminum or other electrically conductive materials including aluminum alloys.

The anode current collector and/or the cathode current collector are preferably each a metal foil with a thickness in the range from 4 μm to 30 μm, especially a ribbon-like metal foil with a thickness in the range from 4 μm to 30 μm. .
However, in addition to foils, the current collectors used can also be other substrates in the form of ribbons, for example metallic or metallized non-woven fabrics, or open-pore metal foams, or even expanded metals. good.

The current collector is preferably provided with corresponding electrode materials on both sides. In some particularly preferred configurations, cells of the invention have the following features: a. ～c. It may be characterized by having at least one of:
a. The strip-shaped main area of the current collector, which is connected to the contact element by welding, has a number of openings.
b. The openings in the main area are circular or square holes, especially punched or drilled holes.
c. The current collector, which is connected to the contact element by welding, is perforated in the main area, in particular by drilling a round hole or a slot.
Preferably, the immediately preceding feature a. and b. , or a. and c. , more preferably the immediately preceding three features a. ～c. are realized in combination with each other.

As a result of the large number of openings, the volume of the current collector is reduced, further reducing its weight. This makes it possible to introduce more active material into the cell and thus significantly increase the energy density of the cell. In this way, increases in energy density in the double-digit percentage range can be achieved.
In some preferred embodiments, the apertures are introduced in the main region in strips by a laser.

The geometry of the opening is in principle not an essential feature of the invention. Importantly, as a result of introducing the aperture, the mass of the current collector is reduced, and the aperture can be filled with active material, so there is more space for the active material within the aperture. That's true.

When introducing an opening, it may be very advantageous to ensure that the maximum diameter of the opening is not too large. The dimensions of the openings should preferably not exceed twice the thickness of the layer of electrode material on the corresponding current collector.

In a particularly preferred configuration, the cell of the invention has the following features: a. Characterized by having:
a. The openings in the current collector, especially in the main region, have a diameter in the range 1 μm to 3000 μm.
Within this preferred range, diameters in the range 10 μm to 2000 μm, preferably 10 μm to 1000 μm, especially 50 μm to 250 μm are more preferred.

Cells of the invention have the following additional features: a. and b. Particularly preferred if it is characterized by having at least one of:
a. The current collector connected to the contact element by welding has, at least in a subsection of the main area, a weight per unit area that is lower than in the free edge strip of the same current collector.
b. The current collector connected to the contact element by welding has fewer openings per unit area compared to the main area, if there are openings in the free edge strip.
Previous feature a. and b. are particularly preferably realized in combination with each other.

Free edge strips of the anode current collector and the cathode current collector delimit the main area on the side of the first longitudinal edge. Preferably, both the anode current collector and the cathode current collector each include free edge strips along both of their longitudinal edges.
An opening characterizes the main area. In other words, the boundary between the main area and the free edge strip corresponds to the transition between the area with openings and the area without openings.
The openings are preferably distributed essentially evenly over the main area.

In a further particularly preferred embodiment, the cell of the invention has the following features: a. ～c. Characterized by having at least one of:
a. The weight per unit area of the current collector in the main region is reduced by 5% to 80% compared to the weight per unit area of the current collector in the free edge strip.
b. In the main area, the current collector has a perforated area in the range of 5% to 80%.
c. In the main area, the current collector has a tensile strength of 20N/mm ² to 250N/mm ² .

Previous feature a. ～c. are particularly preferably realized in combination with each other.

The perforation area, also commonly referred to as the free section, can be determined according to ISO 7806-1983. The tensile strength of the current collector in the main region is reduced compared to a current collector without openings. It can be determined according to DIN EN ISO 527 Part 3.

Preferably, the anode current collector and the cathode current collector are of the same or similar design with respect to the aperture. The energy density improvement that can be achieved in each case is additive. Accordingly, in a preferred embodiment, the cell of the invention further comprises the following features: a. ～c. has at least one of:
a. Both the strip-like main region of the anode current collector and the main region of the cathode current collector are characterized by a large number of openings.
b. The cell comprises as a first contact element a contact element joined by welding to one of the first longitudinal edges and further coupled by welding to the other of the first longitudinal edges. A second metal contact element is provided.
Previous feature a. and b. are particularly preferably realized in combination with each other.
The preferred configuration of the current collector provided with the opening described above is independently applicable to the anode current collector and the cathode current collector.

Solution of the Invention The specific features of the cell are the following two features k. and l. is:
k. The contact element has a circular edge and closes the terminal circular opening of the tubular housing part in a gas-tight and liquid-tight manner.
l. The contact element is electrically connected to one of the first longitudinal edges, and when the pressure in the housing exceeds a threshold, the contact element is in electrical contact with the first longitudinal edge. is or includes a metallic membrane that bends with loss.

Thus, firstly, the contact element of the electrochemical storage element of the invention is used to contact one of the electrodes and at the same time functions as a housing part. Secondly, the contact element has CID functionality thanks to the membrane, which, as the central element of the CID, connects to the electrode assembly very closely and with very low electrical resistance. ing. Thanks to the structure of the invention, compared to conventional CID structures, it is possible to operate with fewer components, since some components assume multiple functions at the same time. Particularly advantageously, therefore, more space is available for the active material. Furthermore, cell assembly is simplified.

Loss of electrical contact with one of the first longitudinal edges, usually when the first longitudinal edge connecting to the contact element breaks away from the contact element as a result of curvature of the membrane. It arises from separation. This preferably breaks the welded joint between the contact element and the first longitudinal edge. However, it is also conceivable that the first longitudinal edge comprises an intended tear line along which the crack occurs. Such an intended tear line may, for example, extend along the boundary between the main area provided with the opening and one of the free edge strips, as described above. If a mechanical stress occurs perpendicular to the main extension direction as a result of membrane curvature, the current collector will tear preferentially along this boundary line.

Formation of the Membrane as a Spring Element For the realization of the solution of the invention, the metallic membrane changes, in a particularly simple and concise case, from a first stable state to a second stable or metastable state above a threshold value. It can be designed as a spring element.
A spring element with a stable first state and a stable second state is one embodiment of a bistable system. Spring elements having a stable first state and a metastable second state are also known under the name "clicker".

The ability to utilize the first and second stable states can preferably be provided by a suitable shape of the spring element. The second state is stable if the spring element remains in the second state even if the pressure within the housing returns to a value below the pressure threshold. In contrast, "metastable" means that as soon as the pressure falls below a pressure threshold, the second state is automatically abandoned in favor of the first state.

When using a contact element with a membrane that is in the form of a spring element or is designed as such, exceeding a threshold value results in an abrupt transition to the second stable or metastable state, so that the first One of the longitudinal edges of the contact element may tear away from the contact element.

If the contact element comprises a membrane in the form of a spring element, a welded joint between one of the first longitudinal edges and the contact element is provided between the first longitudinal edge and the membrane. It is preferable that only the If the contact element takes the form of a spring element, the welded joint between one of the first longitudinal edges and the contact element is exclusively in the central region of the contact element affected by the bending. Preferably present.
Below follows a description of some particularly preferred embodiments of contact elements and their use in particularly preferred variants of the invention.

Preferred embodiment of the electrical attachment of the contact element to the electrode-separator assembly in the form of a contact element/winding

In a first preferred variant of the invention, the energy storage cell has the following four characteristics: a. ～d. has at least one of:
a. The contact elements comprise, as membranes, metal discs and also terminal covers, each of which has a circular circumference.
b. The metal disk is in direct contact with one of the first longitudinal edges and is connected thereto by welding.
c. The metal disk and the terminal cover surround the interior space, and when a threshold is exceeded, the metal disk bends into the interior space.
d. At least one spacer element is arranged within the interior space, which prevents bending into the interior space below a threshold value and collapses and/or compresses above a threshold value.
Previous feature a. and b. It is preferable to realize a combination of the following. Previous feature a. ～d. Particularly preferred is the combination of the following.

The contact element may be composed of a plurality of individual parts, including a metal disc, which parts do not necessarily all have to be composed of metal. In a particularly preferred embodiment, the contact element may comprise a metallic terminal cover, for example with a circular circumference, which terminal cover may be welded onto a metal disc, the edge of the metal disc and the terminal The edges of the cover have approximately or exactly the same diameter as the metal disk so that collectively they form the edges of the contact element. In a further embodiment, the edge of the terminal cover may be surrounded by the edge of a metal disk that is bent radially inward. In preferred embodiments, there may even be a clamp connection between the two individual parts.

The interior space of the cell of the invention is preferably not sealed from the cell's environment. Generally, the terminal cover includes at least one opening through which pressure can be balanced to the environment of the cell. As a result, no back pressure builds up within the interior space when the membrane bends into the interior space.

In order to prevent the metal disk from bending even at pressures below a threshold, in a first preferred variant of the invention spacer elements are provided. The spacer element preferably abuts the metal disc at one end and the terminal cover at the other end to prevent the membrane from bending too quickly into the interior. According to the invention, the spacer elements meet a corresponding desired threshold value. For example, the spacer elements used may be plastic or metal parts that break or plastically deform under a given pressure.

In a development of the first preferred variant of the invention, the cell has three characteristics: a. ～c. has at least one of:
a. The metal disk has on one side thereof at least one depression in the form of a channel and/or a dot, the depression protruding on the other side as at least one elevation in the form of a line and/or a dot. .
b. The side with at least one convexity is in direct contact with one of the first longitudinal edges.
c. The at least one protrusion and the first longitudinal edge are joined via at least one weld point and/or at least one weld seam.
Previous feature a. ～c. Particularly preferred is the combination of the following.

Once the metal disc is bent, the connection with the longitudinal edges to which it is connected must be separated with maximum integrity and reliability. Surprisingly, a reliable separation is possible, especially if channel-shaped and/or dot-shaped depressions are present and at the same time the longitudinal edges are welded to at least one convexity. More preferably, the plurality of beads are formed as elongated depressions.

To ensure that curvature of the metal disk is possible, the metal disk must not be too thick. Generally, for example for a cell with a shape factor of 21×70, a metal disc with a thickness in the range of 0.2 to 0.4 mm will meet the requirements. For larger cells, metal disks with larger wall thicknesses must be used, if appropriate. For smaller cells, the wall thickness must be thinner, if appropriate.

In a preferred development of the metal disc of the cell according to the invention, the cell has the following two characteristics: a. and b. Characterized by having at least one of:
a. The metal disk has a plurality of channel-shaped depressions on one side thereof, preferably in a star-shaped configuration, and the depressions project as linear ridges on the other side.
b. The metal disc comprises at least one weld seam, preferably two parallel weld seams, in each channel-shaped recess as a result of welding the metal disc to the first longitudinal edge.
Previous feature a. and b. Particularly preferred is the combination of the following.

The star-shaped configuration and the double welded seam ensure a good, particularly uniform bond of the metal disk to one of the first longitudinal edges.
For membrane bending, the pressure threshold and the rate of contact release can be adjusted via the configuration of the welds, in particular the number, size and position of the weld seams.

In a particularly preferred development of the first preferred variant of the invention, the cell has the following six characteristics: a. ～f. has at least one of:
a. The contact element comprises not only a metal disc but also a contact sheet.
b. The contact sheet is in direct contact with one of the first longitudinal edges and is connected thereto by welding.
c. The contact sheet is star-shaped and includes a center and at least three extensions that are strip-like and in a star configuration.
d. The metal disk has on one side thereof, in addition to the channel-shaped depression, a star-shaped depression, in which the contact sheet is located.
e. At least one insulating means arranged between the metal disc and the contact sheet insulates the strip-shaped extension from the metal disc.
f. The metal disc and the central part of the contact sheet are connected to each other by welding.
Previous feature a. and b. , feature e. and f. It is preferable to implement this together. Previous feature a. ～f. The realization of all combinations of is particularly preferred.

This embodiment, thanks to the additional contact sheet, ensures virtually optimal electrode attachment without sacrificing low energy density. This is because the solution according to the invention allows a particularly space-saving arrangement of the metal disk and the contact sheet, since the star-shaped recess in the metal disk can accommodate the contact sheet.

In some embodiments, the contact sheet may have at least one channel-shaped and/or dot-shaped depression, like a metal disk. However, the contact sheet is preferably flat and does not have any channel-shaped and/or dot-shaped depressions.

Welding of the metal disc to the center of the contact sheet is preferably realized by only one welding point. This facilitates contact release in case the membrane bends.

The above features a. and b. However, the feature e. and f. In embodiments realized with the contact sheet does not necessarily have to be star-shaped. For example, the contact sheet may also be circular, ie disk-shaped, or polygonal.

In a second preferred variant of the invention, the energy storage cell has the following five characteristics: a. ～e. has at least one of:
a. The contact elements comprise, as membranes, metal discs and also terminal covers, each of which has a circular circumference.
b. The contact element comprises a contact sheet that is in direct contact with one of the first longitudinal edges and is connected to the longitudinal edge by welding.
c. The metal disk and the terminal cover surround the interior space, and when a threshold is exceeded, the metal disk bends into the interior space.
d. At least one spacer element is arranged within the interior space, which prevents bending into the interior space below a threshold value and collapses and/or compresses above a threshold value.
e. The metal disc and the contact sheet are directly connected to each other by welding.
Previous feature a. ～e. Particularly preferred is the combination of the following.

In contrast to the first preferred variant of the invention, there is no direct connection between the metal disc and the first longitudinal edge. A connection exists only between the contact sheet and the first longitudinal edge.

The other components of the contact element and the spacer element may, in a preferred embodiment, be developed as described in connection with the first preferred variant of the invention.

In a third preferred variant of the invention, the energy storage cell has the following five characteristics: a. ～e. has at least one of:
a. The contact element comprises a metal disc with a circular circumference and a contact sheet.
b. The contact sheet is in direct contact with one of the first longitudinal edges and is connected thereto by welding.
c. The metal disc and the contact sheet are separated from each other by at least one electrically insulating spacer.
d. The metal disk is provided with a metal membrane or is formed as a membrane in some areas.
e. The membrane is in electrical contact, preferably directly, with the contact sheet until a threshold value is exceeded.
Previous feature a. ～e. Particularly preferred is the combination of the following.

The metal disc of the contact element does not necessarily have to be a separate component. For example, the base of the housing cup may also function as a metal disc of the contact element. In a third variant of the invention, the CID membrane can be integrated into the base of the housing cup, for example. When the cell pressure exceeds a threshold, the membrane bends outward and the electrical connection to the electrode assembly is severed. A spacer made of electrically insulating material here prevents electrical contact between the metal disk and the contact sheet. The spacer may be a plastic ring, for example.

The membrane may be welded to the contact sheet, inter alia via one or more welding points. However, this is not necessarily the case if, for example, the membrane and the contact sheet are in contact via a spring force.

In a development of the third preferred variant of the invention, the cell has the following features: a. has:
a. The membrane takes the form of a spring element that changes from a first stable state to a second stable or metastable state when a threshold value is exceeded.
The meaning of spring element according to the invention has already been defined above.

In principle, the contact element can likewise be provided with a terminal cover, as in the first preferred variant of the invention. Correspondingly, in a possible development of the third preferred variant of the invention, the cell has the following features a. and b. has at least one of:
a. In addition to the metal disc, the contact element comprises a terminal cover with a circular circumference.
b. The metal disc and the terminal cover surround the interior space, and the membrane bends into the interior space when a threshold is exceeded.
Here, the metal disc and the terminal cover are designed in a preferred embodiment as described in connection with the first preferred variant of the invention.

Variants for closure In principle, it is possible to insert the contact element into the terminal circular opening of the tubular housing part, with or without a seal, for sealing. Correspondingly, in the first preferred closure variant the following is preferred:
a. the cell comprises an annular seal made of electrically insulating material surrounding a circular edge of the contact element; and
b. The contact element is arranged within the tubular housing part, with a seal sealing the terminal circular opening of the tubular housing part, such that the annular seal adjoins the inside of the tubular housing part along the circumferential contact zone and the contact element. It is located.
In the second closure variant, the following is preferred:
a. the contact element is arranged within the tubular housing part such that its edge extends along an inner circumferential contact zone of the tubular housing part; and
b. The edge of the contact element is joined to the tubular housing part via a circumferential weld seam.

Preferably, the tubular housing part has a circular cross-section, at least in the section where the seal adjoins the tubular housing part, so that the edge of the annular seal or contact element can extend inwardly along the circumferential contact zone. . Suitably, this section is in the form of a hollow cylinder for this purpose. Correspondingly, the inner diameter of the tubular housing part in this region matches the outer diameter of the edge of the contact element, in particular the outer diameter of the metal disc, and the seal is pulled into it.

In the case of a contact element in which the seal rests on the edge under tension, cell closure can be achieved by a beading or crimping operation with compression of the seal.

The seal itself may be a conventional polymer seal, which in each case should be chemically resistant to the electrolyte used. Those skilled in the art will recognize suitable sealing materials.

A variant effect of the first closure is that the contact element is electrically isolated with respect to the tubular housing part. The contact elements form the electrical terminals of the cell. In the case of closure according to the second closure variant, the tubular housing part and the contact element have the same polarity.

The weld seam in the second closure variant is preferably formed by welding the edge of the contact element to the tubular housing part using a laser. Alternatively, it is also possible in principle to fasten the metal disc by soldering or adhesive bonding. In the latter case, the contact element can be electrically isolated with respect to the tubular housing part, similar to when using a seal.

Welding the contact element to one of the first longitudinal edges The concept of welding the edge of the current collector to the contact element is from WO 2017/215900A1 or JP 2004-119330A It is already publicly known. This technique allows particularly high current carrying capacity and low internal resistance. With respect to the method of electrically connecting contact elements, in particular further disc-shaped contact elements, to the edges of current collectors, reference is made in full to the contents of WO 2017/215900A1 and JP 2004-119330A. Ru.

In this case, the contact of the first longitudinal edge against the contact element or against a component of the contact element results in a linear contact zone, which is similar to the case with spirally wound electrodes. , extending in a spiral shape. Along or transversely to this linear and preferably spiral-shaped contact zone, the attachment of the longitudinal edges to the contact element or to the components of the contact element is carried out using suitable welded connections. It is possible to achieve maximum uniformity.

Variants of the Housing with Housing Cup In a particularly preferred embodiment of the invention, the energy storage cell has the following features: a. and b. has at least one of:
a. The tubular housing part is part of a housing cup with a circular base.
b. The other of the first longitudinal edges is directly adjacent to the base and is preferably coupled to the base by welding.
Previous feature a. and b. Particularly preferred is the combination of the following.

This variant is particularly suitable for cells according to the first closure variant described above. If the second closure variant is used, a terminal bushing is required, except in the case of the adhesive bond described above.

The use of housing cups has long been known in the construction of cell housings, for example from WO 2017/215900 A1 mentioned at the outset. In contrast, what is not known is to attach the longitudinal edges of the current collector directly to the bottom of the housing cup, as proposed here.

According to the invention, the current collector edges of the positive and negative electrodes, respectively, projecting from the opposite end faces of the electrode-separator assembly in the form of a winding are attached to the housing part, i.e. to the bottom of the cup, and to the above-mentioned A direct connection to the contact element functioning as a closure element is possible and preferred. Therefore, using the available internal volume of the cell housing for the active ingredient approaches its theoretical optimum.

The connection of the other of the first longitudinal edges to the base or the contact sheet basically follows the same construction principle as the connection of the first longitudinal edge to the contact element. Here, the longitudinal edge adjoins the base or the contact sheet, which likewise results in a spirally extending linear contact zone in the case of a spirally wound electrode. Along or transversely to this linear and preferably spiral-shaped contact zone, suitable welded connections are used to maximize the uniformity of the attachment of the longitudinal edges to the base. It is possible to do so.

Variants of the housing with two covers In a further particularly preferred embodiment of the invention, the energy storage cell has the following three features: a. ～c. has at least one of:
a. The tubular housing part has a further terminal circular opening.
b. The cell comprises a closing element with a circular edge that closes off this further tunnel opening.
c. The further closure element for the terminal opening is or comprises a metal disc, the edge of which corresponds to or forms part of the circular edge of the metal closure element.
Previous feature a. ～c. Particularly preferred is the combination of the following.

In this embodiment, the tubular housing part forms a housing cup with the closure element. The housing thus consists of three housing parts, one of which is tubular and the other two (contact element and closing element) close the terminal opening of the tubular part. From a manufacturing point of view, this method offers advantages since, unlike in the case of housing cups, deep drawing tools are not required for the manufacture of tubular housing parts. If the other of the first longitudinal edges is attached directly to the closure element, this essentially provides the same advantages as for the attachment of the housing cup to the base described above.

The tubular housing part in this embodiment is preferably cylindrical or hollow cylindrical. The closing element in the simplest embodiment is a metal disc with a circular circumference. Further preferably, the metal disc of the closure element may be formed similarly to the metal disc of the contact element.

In some preferred embodiments, the closure element, in particular the metal disc, may have a radially inwardly bent edge, so that the closure element has a double-layered edge, for example with a U-shaped cross-section. Has an area.

In a further embodiment, the closure element, in particular the metal disc, may have an edge bent by 90° so as to have an L-shaped cross-section.

In a development of these particularly preferred embodiments, the energy storage cell has the following characteristics: a. ～c. has at least one of:
a. The metal disc of the closure element, or the metal disc forming the closure element, is arranged within the tubular housing part in such a way that its edge extends along the inner circumferential contact zone of the tubular housing part.
b. The edge of the metal disk is joined to the tubular housing part via a circumferential weld seam.
c. The tubular housing part comprises a circular edge bent radially inward around the edge of the closure element, in particular the edge of the metal disc.
More preferably, the above characteristics a. and b. , and, if appropriate, the above features a. ～c. are realized by combining them.

Therefore, in this development it is preferred to fix the closing element by welding into the further terminal opening. Again, in the case of circumferential welded seams, no separate sealing element is required.

This development is particularly preferred if the cell is closed according to the first closure variant described above.

Radial bending of the edges of the closure element is an optional measure that is not necessary for fixation of the closure element, but may nevertheless be appropriate.

In one development, the energy storage cell has the following characteristics a. and b. has one of:
a. The other of the first longitudinal edges directly adjoins the metal disk of the closure element or a metal disk forming the closure element and is preferably joined to the metal disk by welding.
b. The other of the first longitudinal edges is welded to the contact sheet directly adjacent to the metal disc.

As a rule, as in the case of contact elements, there is only an indirect connection between the other of the first longitudinal edges and the metal disc or closure element via the contact sheet. It is also possible to do so here. In this case there is preferably a direct connection between the contact sheet and the closure element, in particular the metal disc of the closure element, by direct welding. Here, the contact sheet may be constructed like the counterpart in the case of the contact element described above.

Here too, the connection of the other of the first longitudinal edges to the metal disc or to the contact sheet of the closure element is basically the same construction principle as in the case of the connection of the first longitudinal edge to the contact element. Follow. The longitudinal edge adjoins a metal disk or contact sheet, which in the case of a spirally wound electrode results in a spirally extending linear contact zone. Along or transversely to this linear and preferably spiral-shaped contact zone, the attachment of the longitudinal edge to the metal disc or to the contact seat of the closure element is carried out using suitable welded connections. It is possible to achieve maximum uniformity.

Housing Materials In particular when the cell of the invention is configured as a lithium-ion battery, the choice of materials for manufacturing the housing cup, the metal disc and/or the contact sheet, as well as the closing element or its components, depends on the corresponding housing parts. It depends on whether an anode current collector or a cathode current collector is installed. Preferred materials are, in principle, the same as those for manufacturing the current collector itself. Thus, the aforementioned housing parts may, for example, be composed of the following materials:
Alloyed or unalloyed aluminum, alloyed or unalloyed titanium, alloyed or unalloyed nickel, alloyed or unalloyed copper, stainless steel (eg 1.4303 or 1.4404 type), nickel plated steel.

In addition, the housing and its components may be constructed from multiple layers of material ("cladding material"), including, for example, one layer of steel and one layer of aluminum or copper. In these cases, the aluminum layer or the copper layer forms, for example, the inside of the housing cup or the base of the housing cup.
Further suitable materials are known to those skilled in the art.

Preferred configuration of electrodes In free edge strips, the metal of the corresponding current collector is preferably free of corresponding electrode material. In some preferred embodiments, the free edge strip does not cover the metal of the corresponding current collector, so that the free edge strip is electrically conductive, for example by welding as described above to the contact element or the closure element. Available for connections involving contact.

In some further embodiments, the metal of the corresponding current collector in the free edge strip is instead more thermally stable than the material coating the current collector and It may be coated in at least some areas with a support material different from the electrode material disposed on.

As used herein, "more thermally stable" means that the support material retains its solid state at the temperature at which the metal of the current collector melts. Therefore, either the support material has a higher melting point than the metal, or the support material sublimes or decomposes only at temperatures where the metal is already molten.

Support materials that can be used in connection with the present invention can in principle be metals or metal alloys, provided that they have a higher melting point than the metal constituting the surface to be coated with the support material. However, in many embodiments, the energy storage cell of the present invention preferably has the following features: a. ～d. has at least one of:
a. The support material is a non-metallic material.
b. The support material is an electrically insulating material.
c. The non-metallic material is a ceramic material, a glass-ceramic material, or a glass.
d. Ceramic materials include aluminum oxide (Al ₂ O ₃ ), titanium oxide (TiO ₂ ), titanium nitride (TiN), titanium aluminum nitride (TiAlN), silicon oxide, especially silicon dioxide (SiO ₂ ), or titanium carbonitride ( TiCN).

According to the invention, the support material more preferably comprises the immediately preceding feature b. Particularly preferably according to the immediately preceding feature d. Follow.

The term "non-metallic material" encompasses plastic, glass, and ceramic materials, among others.

In the context of this specification, the term "electrically insulating material" should be interpreted broadly. In principle, electrically insulating material includes any electrically insulating material, especially polymers.

In the context of this specification, the term "ceramic material" should be interpreted broadly. In particular, ceramic materials are understood to mean carbides, nitrides, oxides, silicides or mixtures and derivatives of these compounds.

The term "glass-ceramic material" means, inter alia, a material comprising crystalline particles embedded in an amorphous glass phase.

The term "glass" in principle means any inorganic glass that meets the criteria regarding thermal stability as defined above and is chemically stable towards any electrolyte present in the cell.

More preferably, the anode current collector is composed of copper or a copper alloy, while at the same time the cathode current collector is composed of aluminum or an aluminum alloy and the support material is aluminum oxide or titanium oxide.

It may further be preferred that the free edge strips of the anode current collector and/or the cathode current collector are coated with a strip of support material.

The main regions, in particular the strip-like main regions of the anode and cathode current collectors, preferably extend parallel to the corresponding edges or longitudinal edges of the current collectors. Preferably, the strip-like main region extends over at least 90%, more preferably over at least 95% of the area of the anode current collector and cathode current collector.

In some preferred embodiments, the support material is applied in strips or lines, preferably directly along the main area of the strip, but does not completely cover the exposed area, so that the corresponding The metal of the current collector is exposed directly along the longitudinal edges.

Other preferred configurations of the energy storage cell The energy storage cell of the present invention may be a button battery. A button cell is cylindrical and has a height smaller than its diameter. Its height is preferably in the range 4 mm to 15 mm. More preferably, the button cell has a diameter within the range of 5 mm to 25 mm. Button batteries are suitable for supplying electrical energy to small electronic devices such as watches, hearing aids, and wireless headphones, for example.

The nominal capacity of button cells of the invention in the form of lithium ion cells is generally up to 1500 mAh. The nominal capacity is preferably in the range 100mAh to 1000mAh, more preferably in the range 100 to 800mAh.

More preferably, however, the energy storage cell of the invention is a cylindrical circular cell. A cylindrical circular cell has a height that is greater than its diameter. Cylindrical round cells are particularly suitable for the high-energy demanding applications mentioned at the outset, for example in the automotive sector or for electric bicycles or for power tools.

The height of the energy storage cell in the form of a circular cell is preferably in the range 15 mm to 150 mm. The diameter of the cylindrical circular cell is preferably in the range 10 mm to 60 mm. Within these ranges, for example 18 x 65 (diameter x height in mm), or 21 x 70 (diameter x height in mm), or 32 x 700 (diameter x height in mm) ), or a form factor of 32×900 (diameter×height in mm) is particularly preferred. Cylindrical circular cells with these shape factors are particularly suitable for powering electric drives in motor vehicles.

The nominal capacity of the cylindrical round cell of the invention in the form of a lithium ion battery is preferably up to 90 000 mAh. For a 21×70 form factor, the cell in one embodiment as a lithium ion battery preferably has a nominal capacity in the range 1500mAh to 7000mAh, more preferably in the range 3000 to 5500mAh. For a form factor of 18×65, the cell in one embodiment as a lithium ion battery preferably has a nominal capacity in the range of 1000 mAh to 5000 mAh, more preferably in the range of 2000 to 4000 mAh.

In the European Union, manufacturer information regarding the nominal capacity of secondary batteries is strictly regulated. For example, information on the nominal capacity of secondary nickel-cadmium batteries is based on measurements according to the IEC/EN 61951-1 and IEC/EN 60622 standards, and information on the nominal capacity of secondary nickel-metal hydride batteries is based on measurements according to IEC/EN 61951-1 and IEC/EN 60622 standards. Information on the nominal capacity of secondary lithium batteries is based on measurements according to the standard IEC/EN 61960; information on the nominal capacity of secondary lead-acid batteries is based on measurements according to the IEC/EN 61056-1 standard. Based on value. Any drawings relating to nominal capacity in the present invention are preferably based on these standards as well.

In embodiments where the cell of the invention is a cylindrical round cell, the anode current collector, cathode current collector, and separator are preferably ribbon-shaped and preferably have the following dimensions:
・Length ranging from 0.5m to 25m,
- Width ranging from 30mm to 145mm.
In this case, the free edge strip extending along the first longitudinal edge and not provided with electrode material preferably has a width of 5000 μm or less.

For a cylindrical round cell with a shape factor of 18x65, the current collector preferably has:
- a width of 56 mm to 62 mm, preferably 60 mm, and
- Length of 2 m or less, preferably 1.5 m or less.

For a cylindrical round cell with a shape factor of 21x70, the current collector preferably has:
- a width of 56 mm to 68 mm, preferably 65 mm, and
- Length of 3 m or less, preferably 2.5 m or less.

In a particularly preferred embodiment of the invention, the energy storage cell of the invention has the following characteristics:
a. The contact element comprises a safety valve that allows pressure to escape from the housing if a further pressure threshold is exceeded.

This safety valve may be, for example, a rupture membrane, a rupture cross, or similar intended rupture site that can be cracked open at a defined positive pressure in the cell to prevent the cell from exploding.

More preferably, the metal disc of the contact element may include a safety valve in the form of a specifically intended rupture site.

Prism Embodiment The use of the contact element, which simultaneously serves as a housing part and has a CID function, firstly for the contact connection to one of the electrodes, is not restricted to energy storage cells with a cylindrical housing. . Rather, it is also possible for an energy storage element comprising a laminate surrounded by a prismatic housing and formed from two or more identical electrode-separator assemblies to be provided with such contact elements.

Accordingly, the invention also comprises the following features a. ~l. Contains an energy storage element with:
a. The energy storage element comprises at least two electrode-separator assemblies having an anode/separator/cathode sequence.
b. The anodes of the assembly are preferably rectangular and each includes an anode current collector having an anode current collector edge.
c. Each anode current collector comprises a main region provided with a layer of negative electrode material and a free edge strip extending along the corresponding anode current collector edge and free of electrode material.
d. The cathodes of the assembly are preferably rectangular and each includes a cathode current collector having a cathode current collector edge.
e. The cathode current collectors each have a main area provided with a layer of positive electrode material and a free edge strip extending along the corresponding cathode current collector edge and free of electrode material.
f. The at least two electrode-separator assemblies are in a stacked configuration, and the stack of assemblies has two terminal portions.
g. The electrode-separator assembly stack is surrounded by a prismatic housing.
h. The anode and cathode are designed and/or arranged with respect to each other such that the anode current collector edge projects from one of the terminal parts and the cathode current collector edge projects from the other of the terminal parts. .
i. The energy storage elements include metallic contact elements in direct contact with their anode current collector edges or their cathode current collector edges.
j. The contact element is connected to the edge by welding and is in direct contact with the edge.
k. The contact element functions as a part of the housing.
l. The contact elements are made of metal, electrically connected to the edges and bonded to the contact elements by welding, bending with loss of electrical contact to these edges when the pressure in the housing exceeds a threshold value. Equipped with a membrane.
Regarding the contact element and its components, the same preferred developments are applicable as in the case of the energy storage cell of the invention.

Further features and advantages of the invention will become apparent from the claims and from the following description of preferred embodiments of the invention in conjunction with the drawings. The individual features herein may be implemented individually or in combination with each other.

1 is a cross-sectional view of a front perspective view of a contact element according to the invention; FIG. 2 is a partial cross-sectional view of the contact element shown in FIG. 1 and a current collector edge secured thereto; FIG. FIG. 2 is a top view of one embodiment of a contact sheet. FIG. 3 is a top view of one embodiment of a metal disk of a contact element. FIG. 6 is a diagram (cross-sectional view) of the energy storage cell of the present invention in the third preferred variant of the present invention described above;

1 and 2 show a contact element 110 comprising a metal disc 111, a metal terminal cover 112, a seal 103 and a spacer element 129. The metal disk 111 and the terminal cover 112 each have a circular circumference. The edges of the terminal cover 112 may be surrounded by the edges of the metal disk 111 that are bent radially inward. The edge of the metal disk 111 and the edge of the terminal cover 112 collectively form the edge of the contact element 110. Seal 103 is stretched over the edge of the contact element.

The spacer element closes the opening 161, which can serve to introduce the electrolyte into the cell housing. To ensure a liquid-tight seal, the spacer element 129 may be welded or soldered to the metal disc 111 for this purpose.

Metal disk 111 and terminal cover 112 surround interior space 116 . The metal disc 111 can bend into the internal space 116 when pressure is applied to its underside. In the assembled state, the lower side faces the interior of the battery housing.

Internal space 116 is not closed. Instead, the terminal cover 112 comprises at least one opening 139 that allows pressure to be balanced against the environment of the cell in which the contact element 110 is provided. As a result, when the metal disk 111 functioning as a membrane bends into the interior space 116, no back pressure builds up within the interior space 116.

A spacer element 129 is provided to prevent the metal disc 111 from bending even at pressures below a threshold value. The spacer element preferably abuts the metal disk 111 at one of its ends and the terminal cover 112 at the other end to prevent the membrane from bending too quickly into the interior 116. do. For example, the spacer element 129 may be a plastic or metal part that breaks or plastically deforms at a given pressure on the membrane.

The metal disk 111 has a channel-shaped depression 179 in the form of a bead. In the area of this bead, the current collector edge 115a is welded.

The contact sheet 113 shown in FIG. 3 is star-shaped and comprises a central portion 113a and three extensions 113b in the form of strips and in a star-shaped configuration. The contact sheet 113 may be welded to the edge of the current collector along the line 113c on the strip-like extension 113b. The contact sheet may, for example, be stamped from a sheet and is preferably flat.

The metal disk 111 shown in FIG. 4 comprises three elongated beads 111c intended to improve the contact connection to the edges of the current collector. The beads 111c are similarly arranged in a star shape. The metal disk 111 may be welded to the edge of the current collector along a line within the bead 111c.

The energy storage cell 100 shown in FIG. 5 comprises a hollow cylindrical housing part 101, which is part of a housing cup 107, with a circular base 107a and a circular opening (defined by an edge 101a). Housing cup 107 is a deep drawn part. The housing cup 107 together with the contact element 110 surrounds an interior 137 in which the electrode-separator assembly 104 in the form of a winding is axially aligned. Contact element 110 includes a metal disc 111 with a circular edge and a contact sheet 113.

The electrode-separator assembly 104 is in the form of a cylindrical winding with two terminal end faces, between which a circumferentially wound jacket extends, which is inside the hollow cylindrical housing part 101. Adjacent to. The electrode-separator assembly is formed from positive and negative electrodes and separators 118 and 119, each ribbon-shaped and spirally wound.

Two end faces 104b and 104c of electrode-separator assembly 104 are formed by the longitudinal edges of separators 118 and 119. Current collectors 115 and 125 protrude from these end faces. The corresponding excess lengths are identified as d1 and d2. To ensure that current collectors 115 and 125 can protrude from end faces 104b and 104c, the ribbon anode and ribbon cathode are offset from each other within electrode-separator assembly 104.

Anode current collector 115 projects from upper end surface 104b of electrode-separator assembly 104, and cathode current collector 125 projects from lower end surface 104c. In the main region, the strip-shaped anode current collector 115 is provided with a layer of negative electrode material 155. A strip-shaped cathode current collector 125 in the main region is provided with a layer of positive electrode material 123 . The anode current collector 115 has an edge strip 117 extending along its longitudinal edge 115a and free of electrode material 155. Instead, a coating 165 of ceramic support material is applied here, thereby stabilizing the current collector in this area. The cathode current collector 125 has an edge strip 121 extending along its longitudinal edge 125a and free of electrode material 123. Instead, a coating 165 of ceramic support material is applied here as well.

The edge 115a of the anode current collector 115 is in direct contact with the contact sheet 113 over its entire length and is bonded to the contact sheet by welding. The contact element 110 therefore serves at the same time for the electrical contact connection of the anode and as a housing part.

The edge 125a of the cathode current collector 125 is in direct contact with the base 107a over its entire length and is coupled to the base by welding. The base 107a thus serves not only as a part of the housing, but also for the electrical contact connection of the cathode.

Housing parts 101 and 110 are electrically isolated from each other by seal 103. The edge 101a of the housing part 101 is bent radially inward around the edge of the metal disc 111 surrounded by the seal 103, securing the metal disc 111 within the circular opening of the tubular housing part 101. The tubular housing part 101 comprises, in the axial direction, a section where a circumferentially wrapped jacket 104a adjoins the inside of the tubular housing part and a contact section where an annular seal 103 adjoins the inside of the tubular housing part. The annular seal 103 is in a compressed configuration in the contact section as a result of the pressure exerted on it by the edge 110a of the contact element 110 and the inside of the tubular housing part 101.

Immediately below the contact section, the housing part 101 is provided with a circumferential bead 133. The bead 133 is less pronounced and projects into the inner interior 137 of the housing part 101 by less than the thickness of the housing wall.

The metal disk 111 includes in its center a metal membrane 151 in the form of a bistable spring element. Membrane 151 bends toward interior 137 and contacts contact sheet 113 . When the pressure in the interior 137 exceeds a threshold, the membrane 151 bends outward and the electrical connection between the metal disc 111 and the contact sheet 113 is broken. In order to ensure that an electrical contact between the metal disk 111 and the contact sheet 113 is possible only via the membrane 151, the contact element 110 further comprises a spacer 189. The spacer is a plastic ring.

Contact sheet 113 is provided with holes 187 to ensure that the space bounded by spacer 189, contact sheet 113, and metal disk 111 is in communication connection with interior 137.

Claims (13)

An energy storage cell (100) having the following characteristics:
a. The cell comprises an electrode-separator assembly (104) having an anode/separator/cathode sequence;
b. said electrode-separator assembly (104) is in the form of a cylindrical winding having two terminal end faces (104b, 104c) and a wound jacket (104a);
c. said cell comprises a housing comprising a metallic tubular housing part (101) with a terminal circular opening (101c);
d. The electrode-separator assembly (104) in the form of a winding is axially arranged within the housing such that the wound jacket (104a) is adjacent to the inside (101b) of the tubular housing part (101). are aligned,
e. the anode is ribbon-shaped and comprises a ribbon-shaped anode current collector (115) having a first longitudinal edge (115a) and a second longitudinal edge;
f. Said anode current collector (115) has a strip-shaped main region provided with a layer of negative electrode material (155) and a strip-shaped main region provided with a layer of negative electrode material (155) extending along said first longitudinal edge (115a) and comprising a layer of said electrode material (155). a free edge strip (117), which is not provided with a free edge strip (117);
g. the cathode is ribbon-shaped and comprises a ribbon-shaped cathode current collector (125) having a first longitudinal edge (125a) and a second longitudinal edge;
h. Said cathode current collector (125) has a strip-shaped main region provided with a layer of positive electrode material (123) and a strip-shaped main region provided with a layer of positive electrode material (123) extending along said first longitudinal edge (125a) and comprising a layer of said electrode material (123). a free edge strip (121), which is not provided with a free edge strip (121);
i. The anode and the cathode are such that the first longitudinal edge (115a) of the anode current collector (115) extends beyond one of the terminal end faces (104b, 104c) and the cathode current collector (125) ) are formed and/or arranged together in said electrode-separator assembly (104) such that said first longitudinal edge (125a) of said terminal end faces (104b, 104c) extends over the other of said terminal end faces (104b, 104c). There is,
j. Said cell has an at least partially metallic contact element ( 110),
And the following additional distinctive features:
k. The contact element (110) has a circular edge (110a) and closes the terminal circular opening (101c) of the tubular housing part (101) in an air-tight and liquid-tight manner, and
l. The contact element (110) is electrically connected to one of the first longitudinal edges (115a, 125a) and is configured to contact the first longitudinal edge when the pressure in the housing exceeds a threshold value. An energy storage cell (100) comprising, being or comprising a metallic membrane (111, 151), bending with loss of electrical contact of said contact element to the longitudinal edges (115a, 125a). Additional features below:
a. Said contact element (110) comprises as a membrane a metal disk (111) and also a terminal cover (112), each having a circular circumference.
b. the metal disk (111) is in direct contact with one of the first longitudinal edges (115a, 125a) and is connected to the longitudinal edge by welding;
c. the metal disk (111) and the terminal cover (112) surround an internal space (116), and when the threshold is exceeded, the metal disk (111) bends into the internal space;
d. at least one spacer element (129) in said interior space (116) which prevents bending into said interior space (116) below said threshold value and collapses and/or compresses when said threshold value is exceeded; 2. The energy storage cell of claim 1, wherein the energy storage cell comprises: Additional features below:
a. The metal disk (111) has at least one channel- and/or dot-shaped depression (179) on one side thereof, and the depression has a linear and/or dot-shaped depression on the other side. prominent as at least one protuberance,
b. said metal disk (111) adjoins one of said first longitudinal edges (115a, 125a) by said side surface having said at least one ridge;
c. at least one of said at least one ridge and said first longitudinal edge (115a, 125a) being joined via at least one weld point and/or at least one weld seam. 3. The energy storage cell of claim 2, comprising: Additional features below:
a. Said metal disk (111) has on one side thereof a plurality of channel-shaped depressions (179), preferably in a star-shaped configuration, said depressions projecting as linear ridges on the other side. ing,
b. Said metal disc (111) has a respective one of said channel-shaped recesses (179) as a result of welding of said metal disc (111) to one of said first longitudinal edges (115a, 125a). 4. The energy storage cell of claim 3, wherein the energy storage cell comprises at least one welded seam. Additional features below:
a. the contact element (110) comprises not only the metal disc (111) but also a contact sheet (113);
b. the contact sheet (113) is in direct contact with one of the first longitudinal edges (115a, 125a) and is connected to the longitudinal edge by welding;
c. said contact sheet (113) is star-shaped and comprises a central part 113a and at least three extensions 113b in the form of a strip and in a star-shaped configuration;
d. The metal disk (111) has on one side thereof, in addition to the channel-shaped depression (179), a star-shaped depression, in which the contact sheet (113) is located. do,
e. at least one insulating means arranged between said metal disk (111) and said contact sheet (113) insulating said strip-shaped extension from said metal disk;
f. 5. According to any one of claims 2 to 4, the metal disc (111) and the central part of the contact sheet (113) have at least one of the following: directly connected to each other by welding. Energy storage cell. Additional features below:
a. Said contact element (110) comprises as a membrane a metal disk (111) and also a terminal cover (112), each having a circular circumference.
b. Said contact element (110) comprises a contact sheet (113) in direct contact with one of said first longitudinal edges (115a, 125a) and connected to said longitudinal edge by welding. prepare,
c. the metal disk (111) and the terminal cover (112) surround an internal space (116), and when the threshold is exceeded, the metal disk (111) bends into the internal space;
d. at least one spacer element (129) in said interior space (116) which prevents bending into said interior space (116) below said threshold value and collapses and/or compresses when said threshold value is exceeded; is placed,
e. Energy storage cell according to claim 1, characterized in that the metal disk (111) and the contact sheet (113) are directly connected to each other by welding. Additional features below:
a. The contact element (110) comprises a metal disk (111) with a circular circumference and a contact sheet (113),
b. the contact sheet (113) is in direct contact with one of the first longitudinal edges (115a, 125a) and is connected to the longitudinal edge by welding;
c. the metal disk (111) and the contact sheet (113) are separated from each other by at least one electrically insulating spacer (189);
d. said metal disk (111) is provided with said metal membrane (151) or is formed as said membrane (151) in some areas;
e. Energy storage cell according to claim 1, characterized in that the membrane (151) is in electrical (preferably direct) contact with the contact sheet (113) until the threshold value is exceeded. Additional features below:
a. Energy storage cell according to claim 7, wherein the membrane (151) has the form of a spring element that changes from a first stable state to a second stable or metastable state when the threshold value is exceeded. Additional features below:
a. The contact element (110) comprises, in addition to the metal disc (111), a terminal cover (112) with a circular circumference.
b. 9. According to claim 7 or 8, the metal disc (111) and the terminal cover (112) surround an internal space (116), and the membrane (151) has a bending into the internal space when the threshold is exceeded. energy storage cells. Additional features below:
a. The cell comprises an annular seal (103) made of electrically insulating material surrounding the circular edge (110a) of the contact element (110).
b. The contact element (110) together with the seal (103) adjoins the inner side (101b) of the tubular housing part (101) along a circumferential contact zone. 10. Arranged in a tubular housing part (101), said contact element (110) having, together with said seal (103), sealing said terminal circular opening (101c) of said tubular housing part (101). Energy storage cell according to any one of 1 to 9. Additional features below:
a. Said contact element (110) is arranged within said tubular housing part (101) such that said edge (110a) thereof extends along a circumferential contact zone of said inner side (101b) of said tubular housing part (101). located in
b. The edge (110a) of the contact element (110) is joined (101) to the tubular housing part (101) via a circumferential weld seam.
Energy storage cell according to any one of claims 1 to 9, comprising: Additional features below:
a. Energy storage cell according to any of the preceding claims, wherein the contact element (110) comprises a safety valve that allows pressure to escape from the housing if a further pressure threshold is exceeded. Additional features below:
a. Energy according to claim 1, characterized in that the metallic membrane (111; 151) has the form of a spring element that changes from a first stable state to a second stable or metastable state when the threshold value is exceeded. storage cell.